回答編集履歴
1
Dictionary(grouping:)
answer
CHANGED
|
@@ -1,7 +1,17 @@
|
|
|
1
1
|
```swift
|
|
2
2
|
let array = ["A", "B", "B", "B", "C", "D", "D"]
|
|
3
|
-
print(
|
|
3
|
+
print(array.reduce(into: [String:Int]()) {$0[$1] = ($0[$1] ?? 0) + 1}.filter {$0.1 > 1}.keys)
|
|
4
4
|
//=> ["B", "D"]
|
|
5
5
|
```
|
|
6
6
|
|
|
7
|
-
と、考えてから**daisuke7**さんの回答に気付く‥。
|
|
7
|
+
と、考えてから**daisuke7**さんの回答に気付く‥。
|
|
8
|
+
|
|
9
|
+
##### Dictionary(grouping:)使用
|
|
10
|
+
|
|
11
|
+
さっそく吸収ｗ
|
|
12
|
+
|
|
13
|
+
```swift
|
|
14
|
+
print(Dictionary(grouping: array) {$0}.filter {$0.value.count > 1}.keys)
|
|
15
|
+
```
|
|
16
|
+
|
|
17
|
+
これくらいのシンプルさなら（見た目的に）大丈夫？
|